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Mandibular Fracture Displacement — MFDS Part 1 MCQ

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ModerateAnatomy (Head & Neck)Mandibular Fracture DisplacementMFDS Part 1

A patient has a displaced unilateral fracture through the body of the mandible, between the mental foramen and the angle. Which muscle group exerts the predominant superior pull on the proximal posterior fragment?

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Correct answer: E — Masseter, medial pterygoid and temporalis

The correct answer is E. The proximal posterior fragment contains the angle, ramus and coronoid process. The masseter and medial pterygoid attach around the angle and ramus as a muscular sling, while temporalis inserts onto the coronoid process; together these mandibular elevators pull the fragment predominantly superiorly. The lateral pterygoid inserts into the condylar neck and articular disc and produces mainly anterior translation, so it is more relevant to condylar-fragment displacement. The anterior belly of digastric and geniohyoid attach near the symphysis and tend to pull the distal anterior segment inferiorly and posteriorly. Mylohyoid is also a suprahyoid muscle and is not the principal superior displacing force on the posterior fragment.

Reference: Panesar K, Susarla SM. Mandibular Fractures: Diagnosis and Management. Seminars in Plastic Surgery. 2021;35(4):238-249. Surgical anatomy and fracture displacement. https://pubmed.ncbi.nlm.nih.gov/34819805/